Aviation Accident Summaries

Aviation Accident Summary SEA95LA165

BUHL, ID, USA

Aircraft #1

N48471

GRUMMAN G-164A

Analysis

SHORTLY AFTER THE PILOT HAD TAKEN OFF WITH A CHEMICAL LOAD TO SPRAY A FIELD, THE ENGINE SUSTAINED A LOSS OF POWER. DURING THE FORCED LANDING, THE AIRCRAFT NOSED OVER AFTER CONTACTING A FENCE, CRUSHING THE FUSELAGE AFT OF THE LOWER WING TRAILING EDGE. THE CHEMICAL LOAD HAD NOT BEEN DUMPED, AND THE EXTRA MASS OF THE LOAD AGGRAVATED THE DAMAGE THAT THE AIRCRAFT SUSTAINED IN THE COCKPIT AREA. THE CABLE FOR MANUAL ACTIVATION OF THE SALVO DOOR WAS FOUND TO BE BROKEN. IT COULD NOT BE DETERMINED IF THE CABLE FAILURE PREEXISTED OR WAS THE RESULT OF THE CRASH. THE #4 CYLINDER EXHAUST ROCKER ARM BOSS WAS FOUND CRACKED AROUND ITS ENTIRE CIRCUMFERENCE, AND THE INTAKE VALVE PUSHROD WAS BENT.

Factual Information

On July 29, 1995, approximately 1215 mountain daylight time (MDT), a Grumman G164, N48471, impacted the terrain about one minute after departing Buhl Municipal Airport, Buhl, Idaho. The commercial pilot, who was the sole occupant, received fatal injuries, and the aircraft sustained substantial damage. The 14 CFR 137 aerial application flight, which was planned for a location about 15 miles northwest of the Buhl airport, was operating in visual meteorological conditions. No flight plan had been filed, and the aircraft was not equipped with an ELT. According to witnesses, the aircraft took off and turned to a heading that would take it to the site of the planned application. It was not observed again for about 30 to 45 seconds, and then was heard to impact the terrain, about 3 to 4 miles from the airport. The FAA inspector who responded to the scene reported that the aircraft had impacted the terrain at a very shallow angle. The pilot had not dumped the chemical load prior to impact. Persons who witnessed the aircraft prior to the crash noted that it was running poorly and backfiring prior to the crash. FAA inspectors noted that the #4 cylinder exhaust rocker arm boss was cracked around its entire circumference, with a bent intake pushrod and a straight exhaust pushrod. The intake valve rocker arm showed contact with the intake valve upper retaining washer. Intake and exhaust valves showed no sign of contact with the piston. Company records indicate that the engine had 1316.8 hours since major overhaul. According to FAA inspectors, the manual salvo door cable was broken, which would have prevented dumping the load, however it could not be determined if the cable had failed prior to or during the crash sequence. The aircraft went through a fence and nosed over during the forced landing. The fuselage, aft of the training edge of the lower wing, was extensively crushed and twisted. An autopsy was performed on the pilot by Dr. Carl Staones, at Magic Valley Regional Medical Center, Twin Falls, Idaho. The pathologist stated that the "cause of death was laceration of cerebral peduncles due to massive head injury incurred in [the] aircraft crash." Toxicological testing was performed by the FAA, with negative results.

Probable Cause and Findings

THE LOSS OF POWER DUE TO THE FAILURE OF AN ENGINE CYLINDER. THE CHEMICAL LOAD WAS NOT DUMPED FOR UNDETERMINED REASONS AND CONTRIBUTED TO THE SEVERITY OF INJURIES.

 

Source: NTSB Aviation Accident Database

Get all the details on your iPhone or iPad with:

Aviation Accidents App

In-Depth Access to Aviation Accident Reports